/**
 * @file ymodem.c
 * @author zhuxuanlin (you@domain.com)
 * @brief
 * @version 0.1
 * @date 2024-05-22
 *
 * @copyright Copyright (c) 2024
 *
 */

#include <stdio.h>
#include <string.h>
#include "ymodem.h"

#define SOH 0x01
#define STX 0x02
#define EOT 0x04
#define ACK 0x06
#define NAK 0x15
#define CAN 0x18
#define charC 0x43

#define PACKET_SIZE 128
#define PACKET_1K_SIZE 1024
#define PACKET_OVERHEAD 5
#define PACKET_TIMEOUT 2000
#define PACKET_TIMEOUT_TIMES 15

typedef enum{
    YM_FILEHEADER = 2,
    YM_DATA_TRANS,
    YM_DATA_OVER,
    YM_ABORT_TRANS
}ym_process;

static ymodem_st ym = {
    .get_data = 0,
    .put_data = 0
};
int ymodem_register(int (*put_data)(char* data,unsigned int len,unsigned int mstime),
                    int (*get_data)(char* data,unsigned int len,unsigned int mstime))
{
    ym.put_data = put_data;
    ym.get_data = get_data;
}

static const unsigned short crc_table[256] =
{
    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
    0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
    0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
    0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
    0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
    0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
    0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
    0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
    0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
    0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
    0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
    0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
    0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
    0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
    0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
    0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
    0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
    0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
    0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
    0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
    0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
    0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
    0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
    0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
    0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
    0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
    0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
    0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
    0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
    0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
    0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
    0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
};

static unsigned short crc16(unsigned char *q, int len)
{
    unsigned short crc = 0;

    while (len-- > 0)
        crc = (crc << 8) ^ crc_table[((crc >> 8) ^ *q++) & 0xff];
    return crc;
}


static int __recv_packet(char* data,unsigned int* len, unsigned char packet_num,unsigned int mstime)
{
    if(len == NULL || data == NULL)
    {
        return -1;
    }

    char ym_packet[PACKET_1K_SIZE+PACKET_OVERHEAD];
    memset(ym_packet,0,sizeof(ym_packet));

    
    int ret = ym.get_data(ym_packet,1,PACKET_TIMEOUT);
    if(ret < 0 )
    {
        return -1;
    }
    if(ym_packet[0] != SOH &&  ym_packet[0] != STX)
    {
        if(ym_packet[0] == EOT)
        {
            return 0;
        }
        return -2;
    }
    long packet_len = (ym_packet[0] == SOH)?PACKET_SIZE:PACKET_1K_SIZE;

    ret = ym.get_data(&ym_packet[1],packet_len+4,PACKET_TIMEOUT);

    if(ret < 0 )
    {
        return -3;
    }
    if(!(ym_packet[1] ==  (char)packet_num && ym_packet[2] == (char)(~packet_num)))
    {
        char ack = NAK;
        ym.put_data(&ack,1,PACKET_TIMEOUT);
        return -4;
    }
    unsigned short crc = crc16(&ym_packet[3] , packet_len);

    if(ym_packet[packet_len + 3] == (char)((crc >> 8) & 0xFF) &&
        ym_packet[packet_len + 4] == (char)(crc & 0xFF))
    {
        memcpy(data,&ym_packet[3],packet_len);
        *len = packet_len;
    }
    else
    {
        return -6;
    }

    return packet_len;
}

static int __recv_filename(char* filename,unsigned long* filesize ,unsigned int mstime)
{
    char ym_packet[PACKET_1K_SIZE];
    memset(ym_packet,0,sizeof(ym_packet));
    unsigned long plen = 0;
    int ret = __recv_packet(ym_packet,&plen,0,mstime);
    if(ret < 0 || plen != PACKET_SIZE)
    {
        return -1;
    }

    if(filename == NULL || filesize == NULL)
    {
        for(int i = 0;i<PACKET_SIZE;i++)
        {
            if(ym_packet[i] != 0)
            {
                return -2;
            }
        }
        return 1;
    }
    int i = 0;

    while (ym_packet[i] != 0 && i < PACKET_SIZE) {
        filename[i] = ym_packet[i];
        i++;
    }

    i++;
    unsigned long fsize = 0;

    while (ym_packet[i] != 0 && i < PACKET_SIZE) {
        fsize = fsize * 10 + (ym_packet[i] - '0');
        i++;
    }

    *filesize = fsize;

    return 0;
}


int ymodem_recv(char *buff, long bufsize, char *filename)
{
    if (!ym.get_data || !ym.put_data) {
        return -1;  // 无效的功能指针
    }
    if(!buff || bufsize <= 0 || !filename )
    {
        return -1;
    }

    int rerty_times = PACKET_TIMEOUT_TIMES;
    int ret = -1;
    char ym_tbuf[2] = {0,0},ym_rchar = 0;
    long recv_bytes = 0 , single_packet_size = 0,file_size = 0;

    unsigned char __recv_flags = 0;

    ym_process process = YM_FILEHEADER;

    do{
        switch (process)
        {
        case YM_FILEHEADER:
            ym_tbuf[0] = charC;
            ym.put_data(&ym_tbuf[0],1,PACKET_TIMEOUT);
            ret = __recv_filename(filename,&file_size,PACKET_TIMEOUT);
            if(ret < 0)
            {
                rerty_times--;
            }
            else
            {
                if(file_size > bufsize)
                {
                    return -2;
                }
                ym_tbuf[0] = ACK;
                ym_tbuf[1] = charC;
                ym.put_data(ym_tbuf,2,PACKET_TIMEOUT);
                __recv_flags ++;
                process = YM_DATA_TRANS;
            }
            break;
        case YM_DATA_TRANS:
            ret = __recv_packet(&buff[recv_bytes],&single_packet_size,__recv_flags,PACKET_TIMEOUT);
            if(ret > 0)
            {
                recv_bytes += single_packet_size;
                __recv_flags++;
                ym_tbuf[0] = ACK;
                ym.put_data(ym_tbuf,1,PACKET_TIMEOUT);
                if(recv_bytes  > file_size + PACKET_1K_SIZE)
                {
                    int ack = CAN;
                    ym.put_data(&ack,1,PACKET_TIMEOUT);
                }
            }
            else if(ret == 0)
            {
                process = YM_DATA_OVER;
            }
            else
            {
                ym_tbuf[0] = NAK;
                ym.put_data(ym_tbuf,1,PACKET_TIMEOUT);  
            }

            break;
        case YM_DATA_OVER:
            ym_tbuf[0] = ACK;
            ym_tbuf[1] = charC;
            ym.put_data(ym_tbuf,2,PACKET_TIMEOUT);
            process = YM_ABORT_TRANS;
            break;
        case YM_ABORT_TRANS:
            ret = __recv_filename(NULL,NULL,PACKET_TIMEOUT);
            if(ret < 0)
            {
                rerty_times--;
            }
            else
            {
                ym_tbuf[0] = ACK;
                ym.put_data(ym_tbuf,1,PACKET_TIMEOUT);
                return recv_bytes;
            }
            break;
        default:
            break;
        }

    }while(rerty_times != 0);
    return -1;
}

static int __send_packet(char* data,unsigned int len, unsigned char packet_num,unsigned int mstime)
{

    if(len>PACKET_1K_SIZE || data == NULL)
    {
        return -1;
    }

    char ym_packet[PACKET_1K_SIZE+PACKET_OVERHEAD];
    memset(ym_packet,0,sizeof(ym_packet));
    
    int packet_len = (len<=PACKET_SIZE)?PACKET_SIZE:PACKET_1K_SIZE;

    ym_packet[0] = (packet_len == PACKET_SIZE)?SOH:STX;
    ym_packet[1] = packet_num;
    ym_packet[2] = ~packet_num;


    memcpy(&ym_packet[3],data,len);

    unsigned short crc = crc16(&ym_packet[3] , packet_len);
    ym_packet[packet_len +3] = (crc >> 8) & 0xFF; // Append the higher byte of the CRC.
    ym_packet[packet_len +4] = crc & 0xFF; // Append the lower byte of the CRC.

    int ret = ym.put_data(ym_packet,packet_len+PACKET_OVERHEAD,mstime);

    return (ret > 5)?ret -5:ret;
}

static int __send_filename(char* filename,unsigned long filesize ,unsigned int mstime)
{
    char ym_packet[PACKET_SIZE];
    memset(ym_packet,0,sizeof(ym_packet));
    unsigned char plen = 0;

    if(filename != NULL || filesize != 0)
    {
        plen = sprintf(ym_packet,"%s", filename); // 文件名
        plen++;
        plen += sprintf(&ym_packet[plen], "%d", filesize);
        return __send_packet(ym_packet,plen,0,mstime);
    }
    return __send_packet(ym_packet,PACKET_SIZE,0,mstime);
}


int ymodem_send(char *buff,long bufsize, const char *filename)
{
    if (!ym.get_data || !ym.put_data) {
        return -1;  // 无效的功能指针
    }

    if(!buff || bufsize == 0 || !filename)
    {
        return -1;
    }

    int rerty_times = PACKET_TIMEOUT_TIMES;
    int ret = -1;
    char ym_rbuf[2] = {0,0},ym_tchar = 0;
    long sent_bytes = 0 , single_packet_size = 0;
    unsigned char __send_flags = 0;

    ym_process process = YM_FILEHEADER;

    do{
        switch (process)
        {
        case YM_FILEHEADER:
            ret = ym.get_data(ym_rbuf,1,PACKET_TIMEOUT);
            if(ret == 1 && ym_rbuf[0] == charC)
            {
                ret = __send_filename(filename,bufsize,PACKET_TIMEOUT);
                ret = ym.get_data(ym_rbuf,2,PACKET_TIMEOUT);
                if(ret == 2 && ym_rbuf[0] == ACK && ym_rbuf[1] == charC)
                {
                    __send_flags++;
                    process = YM_DATA_TRANS; 
                }
                else if(ret < 0)
                {
                    rerty_times--;
                }
            }
            else
            {   
                rerty_times--;
            }
            break;
        case YM_DATA_TRANS:
            // 单次发送数据量
            single_packet_size = (bufsize - sent_bytes > PACKET_1K_SIZE) ? PACKET_1K_SIZE : bufsize - sent_bytes;
            ret = __send_packet(&buff[sent_bytes], single_packet_size,__send_flags,PACKET_TIMEOUT); // 发送数据包
            ret = ym.get_data(ym_rbuf,1,PACKET_TIMEOUT);
            if(ret == 1 && ym_rbuf[0] == ACK)
            {
                __send_flags++;
                sent_bytes += single_packet_size;
                if(sent_bytes >= bufsize || sent_bytes < 0)
                {
                    process = YM_DATA_OVER; 
                }
            }
            else if(ret == 1 && ym_rbuf[0] == NAK)
            {
                rerty_times--;
                // 重发
            }
            else if(ret == 1 && ym_rbuf[0] == CAN)
            {
                break;
            }
            else if(ret < 0)
            {
                rerty_times--;
            }
            break;
        case YM_DATA_OVER:
            ym_tchar = EOT;
            ret = ym.put_data(&ym_tchar,1,PACKET_TIMEOUT);
            ret = ym.get_data(ym_rbuf,1,PACKET_TIMEOUT);
            if(ret == 1 && ym_rbuf[0] == ACK) 
            {
                ret = ym.get_data(ym_rbuf,1,PACKET_TIMEOUT);
                if(ret == 1 && ym_rbuf[0] == charC)
                {
                    process = YM_ABORT_TRANS; 
                }

            } 
            else if(ret == 1 && ym_rbuf[0] == NAK)  
            {
                // 重发
            }
            else if(ret < 0)
            {
                rerty_times--;
            }      


            break;
        case YM_ABORT_TRANS:
            ret = __send_filename(NULL,0,PACKET_TIMEOUT);
            ret = ym.get_data(ym_rbuf,1,PACKET_TIMEOUT);
            if(ret == 1 && ym_rbuf[0] == ACK )
            {
                // 正常退出
                return sent_bytes;
            }
            else if(ret < 0)
            {
                // 部分异常退出
                return 1;
            }
            break;
        default:
            break;
        }

    }while(rerty_times != 0);
    return -1;
}



